WASHINGTON -- Republican leaders tried to ignore it. They tried to talk it to death, amend it into oblivion, challenge its constitutionality and deny its political relevance.

But despite the most daunting parliamentary challenges, a bipartisan measure to overhaul the campaign finance system has survived, and remarkably, it is likely to pass the House this week. After four months and 44 hours of debate, legislation to ban so-called "soft money" and sharply restrict attack ads should come to a vote in the House today.

"We've crossed a minefield, and we're still intact," Rep. Christopher Shays, a Connecticut Republican and co-author of the bill, declared Friday, after fending off the last 10 amendments. "This is the kind of bill that won't die."

Senate Republican leaders say they have no plans to take up the issue again this year. The Senate is on its month-long August recess, and leaders hope to adjourn for the year in early October. Even an aide to Sen. John McCain of Arizona, the bill's leading Republican advocate in the Senate, said he sees no way it can reach President Clinton's desk for a promised signature.

But proponents insist a strong House vote could force the Senate to act. Democrats have vowed, if necessary, to attach the legislation to any bill that reaches the Senate floor. And they appear driven by a near-religious zeal.

"This bill has one thing behind it that makes it unstoppable: the need for reform," said Rep. Sander M. Levin, a Michigan Democrat. "We're right on this issue."

Disgust over the fund-raising excesses of both parties in 1996 fueled the drive for the first sweeping overhaul of the campaign finance system since Watergate. Interest groups that have long advocated controls on campaign spending hoped this year to tap a wave of public fears that big-money campaign contributors had attained too strong a voice in the political system.

Campaign fund raising, which shattered all records before the 1996 elections, goes on unabated. The Republican and Democratic parties raised nearly $116 million in soft money during the first 18 months of the 1998 campaign cycle, more than double the $50 million they raised during a comparable period in 1994, the last nonpresidential election, according to Common Cause, a group that advocates campaign spending curbs.

Variety of opposing groups

But advocates came up against dogged opposition from Republican leaders -- and even some traditional Democratic allies like the American Civil Liberties Union -- who contend that curbs on campaign spending represent an unconstitutional gag on free speech. Democrats contend GOP opposition is fueled largely by that party's overwhelming fund-raising advantage in the current system. So far in the 1998 soft money sweepstakes, Republicans have out-raised Democrats, $70 million to $45.8 million.

Yet a coalition of House members spanning the political spectrum has kept the issue alive against exceptionally long odds. The bill would ban soft money, the unregulated campaign donations to political parties ostensibly for "party-building" activities. Those contributions have increasingly been used for overt campaign activities like advertisements.

The bill would sharply restrict political advertising funded by interest groups in the final 60 days of a campaign, and would require that individuals or groups spending more than $1,000 in the last 20 days reveal their identities.

Long road to reform

A nearly identical measure died in the Senate earlier this year. House Republican leaders tried to kill the issue shortly after its Senate demise through parliamentary maneuvering, but they were forced to bring it back up in April after an intraparty Republican revolt.

But there was a catch: Republican leaders -- insisting they could only back the most open debate possible -- said they would accept virtually any amendment proposed and any version of campaign finance reform members could draft. Debate and votes would take months, and whichever version of campaign finance legislation could garner the most votes would pass the House.

More than 50 amendments and a dozen versions of campaign finance reform emerged. Some amendments were designed just embarrass Democrats. House Republican Whip Tom DeLay pushed a measure aimed at Vice President Gore's now-infamous contention that "no controlling legal authority" barred him from making fund-raising phone calls from his office. DeLay's amendment, adopted 360-36, contended that there is such a controlling legal authority.

'Poison pills'

But some proposals were clearly written to scuttle the campaign finance bill by inserting controversial measures many Democrats could not support. Measures included requiring individuals to present proof of citizenship to register to vote, prohibiting bilingual ballots and voting materials, and forcing unions to get annual written consent from members before using dues for political purposes.